NRF52840 dongle USB bootloader with external power supply

RE: NRF52840 dongle USB bootloader with external power supply

smangold — Fri, 05 Jun 2020 11:40:57 GMT

Hi, thanks for this information. I find the USB Dongle extremely useful, but wasn't sure about programming it once it is connected to external supply. Very helpful!!

RE: NRF52840 dongle USB bootloader with external power supply

ketiljo — Mon, 18 May 2020 10:17:44 GMT

No, there are no other components on the dongle. If the current draw is higher on the dongle, it's possibly damaged somehow.

RE: NRF52840 dongle USB bootloader with external power supply

scttnlsn — Sat, 16 May 2020 14:34:57 GMT

I got it working but the current consumption is very high. ~600uA whereas the same program running on the NRF52840 DK only consumes around 75uA. Are there other components that could be sinking some current?

RE: NRF52840 dongle USB bootloader with external power supply

ketiljo — Thu, 14 May 2020 10:20:14 GMT

If you break SB2 and connect SB1, you will just disable the regulator so that you can power the chip externally. VBUS is still connected to the VBUS pin of the nRF52840 to power the USB-PHY. Make sure SB2 is completely disconnected, else you may damage the chip when VBUS is applied to the USB connector. I can't see why it shouldn't work, unless something is broken.

RE: NRF52840 dongle USB bootloader with external power supply

scttnlsn — Tue, 12 May 2020 21:18:11 GMT

I have 3v (from 2 AA batteries in series) across VDD OUT and GND. I press the bootloader reset button (and get a red pulsing LED) and then try to flash my firmware with nrfutil but I get the following error:

pc_ble_driver_py.exceptions.NordicSemiException: Serial port could not be opened on /dev/ttyACM0. Reason: could not open port /dev/ttyACM0: [Errno 2] No such file or directory: '/dev/ttyACM0'

I do not get this error when flashing an unmodified dongle powered via USB 5v.

RE: NRF52840 dongle USB bootloader with external power supply

ketiljo — Mon, 11 May 2020 11:30:02 GMT

Yes, you can still use the USB interface, but you must power the dongle from the external power supply.